Arsenal midfielder Fabregas was named Young Player of the Year - an award which Ronaldo also won in 2007 - at a star-studded ceremony at London's Grosvenor House Hotel on Sunday night.
United are currently preparing for the second leg of their Champions League semi-final against Barcelona on Tuesday night.
Ronaldo said: "I feel very happy. When you work all season to play good, to do something for the team, to do your contribution for the team and then at the end of the season the PFA give you this award, it is a great moment, it is an honour, a pleasure.
"It is a great motivation to carry on like that, to work more and get better.
"I feel very good but it is not just my award, my team-mates have helped me a lot this season.
"They give me good passes to score goals - and I score - but it is a good moment for me.''
Ronaldo, who joined United in a £12.24million move from Sporting Lisbon in 2003, feels he has improved considerably during his time at Old Trafford.
As well as scooping both PFA awards last year he came third in the FIFA World Player of the Year poll and he is looking forward to achieving even more success, individually and collectively, with United in future.
The Portuguese star added: "I am sure I am better player than four or five years ago. Than last year? I have improved a little bit better still.
"This is my ambition to learn more and play better and I think I am in the right place. I want to carry on and this for me is a good moment to stay at the club and play at the best level."